Bu çalışma, Kanada Sağlık Araştırmaları Enstitüsü tarafından desteklendi.

Deneyleri, sıçan, sığınma dizenin sonunda bulunan bir gıda pelet kokulu bir dize dışa gezisinden sonra eve dönmek için challanged edildi bir roman görev istismar ederek ölü hesaplaşma navigasyon karşı pilot hipokampus katkısı inceledi. Kontrol sıçanlar, hem mekansal ve ölü hesaplaşma stratejileri kullanarak verimli bir navigasyon. Fimbria-forniks lezyonu olan sıçan mekansal bir strateji kullanarak başarıyla navigasyon ama ölü hesaplaşma kullanmak zorunda engelli. Bu sonuçlar, hipokampal fo...

<table><tbody><tr><td>Sodium pentobarbital</td><td> Reagent</td><td>Sigma-Aldrich</td><td>p3761-25g</td><td></td></tr><tr><td>Atropine methyl nitrate</td><td>Reagent</td><td>Sigma-Aldrich</td><td>a0382-5g</td><td></td></tr><tr><td>Rodent pellets</td><td>Animal food</td><td>BIO-SERV</td><td></td><td></td></tr></tbody></table>

a video demonstration of preserved piloting by scent tracking but impaired dead reckoning after fimbria-fornix lesions in the rat

Pilot projeler ve çok farklı bir işaret takımyıldızları ve hesaplama işlemleri (Darwin, 1873 ölü hesaplaşma gezinme stratejileri kullanır; Barlow, 1964; O&#39;Keefe ve Nadel, 1978; Mittelstaedt ve Mittelstaedt, 1980; Landeau ve ark, 1984; Etienne, 1987; Gallistel, 1990, Maurer ve Séguinot, 1995). Ölü hesaplaşma, kendi hareketleri ile üretilen ipuçlarının entegrasyon gerektirmektedir Pilotaj, nispeten istikrarlı bir dış (görsel, koku alma, işitme) ipuçları arasındaki ilişkileri kullanımını gerektirir. Hayvanlar vestibüler reseptörleri kendi kendine hareket bilgileri elde etmek için, ve muhtemelen kas ve eklem reseptörleri hareketi oluşturmak komutları efference kopyası. Bir hayvan hareketleri nedeniyle görsel akışları, işitsel ve koku uyaranlara kullanabilirsiniz. Pilot bir strateji, bir hayvan kullanmak, çevresindeki yerlere yön ve mesafeleri belirlemek için bir ölü hesaplaşma stratejisi kullanarak ise sadece sol bir konuma dönmek için önceki hareketleri tarafından oluşturulan ipuçları entegre edebilirsiniz geometrik hesaplamalar kullanabilirsiniz. Ölü hesaplaşma halk dilinde &quot;yön duygusu&quot; ve &quot;mesafe duygusu denir.&quot; Hipokampus pilot (O&#39;Keefe ve Nadel, 1978; O&#39;Keefe ve Speakman, 1987) yer alması önemli bir delil olmamasına rağmen; Whishaw ve Maaswinkel, 1998, davranışsal (Whishaw ve ark, 1997 kanıtlar da vardır; Maaswinkel ve Whishaw, 1999), modelleme (Samsonovich ve McNaughton, 1997) ve elektrofizyolojik (O&#39;Mare ve ark, 1994; Keskin ve ark, 1995; Taube ve Burton, 1995; Blair ve Keskin, 1996; McNaughton ve ark. , 1996; Wiener, 1996; hipokampal formasyon ölü hesaplaşma katkısı olduğunu Golob ve Taube, 1997) çalışmalar. Ancak navigasyon iki form hipokampus göreceli katkısı hala belirsiz. Dudchenko ve ark, 1997; Martin ve ark hayvanlar, stratejiler ve ipuçları (Etienne ve ark, 1996 bunların kullanımı çok esnek, çünkü Normalde, bir hayvanın ölü bir hesaplaşma ve strateji pilot olduğunu emin olmak zor. , 1997; 1999 Maaswinkel ve Whishaw). Bu stratejilerin kullanımı hipokampus göreceli katkısı incelemek için işaret belirtimi sorunu çözmek için mevcut video gösterilerinin hedefi oldu. Sıçanlarda pelet açık alanda gizli büyük bir yiyecek elde etmek için doğrusal veya çokgen kokulu yollar takip etmesi yeni bir görev eğitilmiştir. Sıçan, sığınak, doğruluk ve ana üssü olan bağımlı değişkenler (Whishaw ve Tomie, 1997) dönmek için kullanılır ipuçları geri yiyecek taşımak için bir eğilimine sahip. Fareler yiyecek, sığınak ulaşmak için aa ölü hesaplaşma strateji kullanmak için bir hayvan zorlamak için gözleri bağlanmış, test edilmiştir ve onlar görmek değil. Hangi bir spektral dalga boyu, kızılötesi ışık altında ve bazı deneyler koku izi ek bir kez kaldırılmış oldu hayvansal gıda ulaştı. Hipokampal formasyon bilgi akışı (Bland, 1986) bozabilir hipokampus, fimbria-forniks (FF) lezyonlar, göreceli katkısını incelemek için, bellek (Gaffan ve Gaffan, 1991) zarar ve mekansal açıkları üretmek (Whishaw ve Jarrard 1995) kullanılmıştır.

Watch this Scientific Journal Video about A Video Demonstration of Preserved Piloting by Scent Tracking but Impaired Dead Reckoning After Fimbria-Fornix Lesions in the Rat at JoVE.com

A Video Demonstration of Preserved Piloting by Scent Tracking but Impaired Dead Reckoning After Fimbria-Fornix Lesions in the Rat

Bir pilot koku izleme görevi sıçan, gıda ile görsel bir koku izi kullanarak ya da kızılötesi ışık kullanarak ölü hesaplaşma bir sığınak dönmek için yetenek, önceki hareketleri entegre kayıt, hipokampus ölü hesaplaşma için gerekli olduğunu göstermektedir.

Rat fimbria-forniks Lezyonlar Koku Takibi sonra ancak Engelli Dead Reckoning Pilotaj Korunan bir video gösteri

Piloting and dead reckoning navigation strategies use very different cue constellations and computational processes (Darwin, 1873; Barlow, 1964; ...

a-video-demonstration-preserved-piloting-scent-tracking-but-impaired

Research

JoVE Journal

Biology

11.8K Görüntüleme.  Canadian Centre for Behavioural Neuroscience, University of Lethbridge. Bir pilot koku izleme görevi sıçan, gıda ile görsel bir koku izi kullanarak ya da kızılötesi ışık kullanarak ölü hesaplaşma bir sığınak dönmek için yetenek, önceki hareketleri entegre kayıt, hipokampus ölü hesaplaşma için gerekli olduğunu göstermektedir.

Video: A Video Demonstration of Preserved Piloting by Scent Tracking but Impaired Dead Reckoning After Fimbria-Fornix Lesions in the Rat

The Double-H Maze: A Robust Behavioral Test for Learning and Memory in Rodents

Spatial cognition research in rodents typically employs the use of maze tasks, whose attributes vary from one maze to the next. These tasks vary by their behavioral flexibility and required memory duration, the number of goals and pathways, and also the overall task complexity. A confounding feature in many of these tasks is the lack of control over the strategy employed by the rodents to reach the goal, e.g., allocentric (declarative-like) or egocentric (procedural) based strategies. The double-H maze is a novel water-escape memory task that addresses this issue, by allowing the experimenter to direct the type of strategy learned during the training period. The double-H maze is a transparent device, which consists of a central alleyway with three arms protruding on both sides, along with an escape platform submerged at the extremity of one of these arms.
Rats can be trained using an allocentric strategy by alternating the start position in the maze in an unpredictable manner (see protocol 1; &#167;4.7), thus requiring them to learn the location of the platform based on the available allothetic cues. Alternatively, an egocentric learning strategy (protocol 2; &#167;4.8) can be employed by releasing the rats from the same position during each trial, until they learn the procedural pattern required to reach the goal. This task has been proven to allow for the formation of stable memory traces.
Memory can be probed following the training period in a misleading probe trial, in which the starting position for the rats alternates. Following an egocentric learning paradigm, rats typically resort to an allocentric-based strategy, but only when their initial view on the extra-maze cues differs markedly from their original position. This task is ideally suited to explore the effects of drugs/perturbations on allocentric/egocentric memory performance, as well as the interactions between these two memory systems.

The goal of this protocol is to investigate spatial cognition in rodents. The double-H water maze is a novel test, which is particularly useful to elucidate the different components of learning, consolidation and memory, as well as the interplay of memory systems.

Çift H Maze: Kemirgenler A Sağlam Davranış Öğrenme için test ve Hafıza

Spatial cognition research in rodents typically employs the use of maze tasks, whose attributes vary from one maze to the next. These tasks vary by their ...

Davranış

Detecting Behavioral Deficits in Rats After Traumatic Brain Injury

With the increasing incidence of traumatic brain injury (TBI) in both civilian and military populations, TBI is now considered a chronic disease; however, few studies have investigated the long-term effects of injury in rodent models of TBI. Shown here are behavioral measures that are well-established in TBI research for times early after injury, such as two weeks, until two months. Some of these methods have previously been used at later times after injury, up to one year, but by very few laboratories. The methods demonstrated here are a short neurological assessment to test reflexes, a Beam-Balance to test balance, a Beam-Walk to test balance and motor coordination, and a working memory version of the Morris water maze that can be sensitive to deficits in reference memory. Male rats were handled and pre-trained to neurological, balance, and motor coordination tests prior to receiving parasagittal fluid percussion injury (FPI) or sham injury. Rats can be tested on the short neurological assessment (neuroscore), the beam-balance, and the Beam-Walk multiple times, while testing on the water maze can only be done once. This difference is because rats can remember the task, thus confounding the results if repeated testing is attempted in the same animal. When testing from one to three days after injury, significant differences are detected in all three non-cognitive tasks. However, differences in the Beam-Walk task were not detectable at later time points (after 3 months). Deficits were detected at 3 months in the Beam-Balance and at 6 months in the neuroscore. Deficits in working memory were detected out to 12 months after injury, and a deficit in a reference memory first appeared at 12 months. Thus, standard behavioral tests can be useful measures of persistent behavioral deficits after FPI.

The goal of the behavioral tests presented here is to detect functional deficits in rats after traumatic brain injury. Four specific tests are presented that detect deficits in behaviors to reflect the damage to specific brain areas at times extending to one year after injury.

Travmatik beyin hasarı sonra Sıçanlarda algılama davranış açıkları

With the increasing incidence of traumatic brain injury (TBI) in both civilian and military populations, TBI is now considered a chronic disease; however, ...

Use of Rotorod as a Method for the Qualitative Analysis of Walking in Rat

High speed videoanalysis of the details of movement can provide a source of information about qualitative aspects of walking movements. When walking on a rotorod, animals remain in approximately the same place making repetitive movements of stepping. Thus the task provides a rich source of information on the details of foot stepping movements. Subjects were hemi-Parkinson analogue rats, produced by injection of 6-hydroxydopamine (6-OHDA) into the right nigrostriatal bundle to deplete nigrostriatal dopamine (DA). The present report provides a video analysis illustration of animals previously were filmed from frontal, lateral, and posterior views as they walked (15). Rating scales and frame-by-frame replay of the video records of stepping behavior indicated that the hemi-Parkinson rats were chronically impaired in posture and limb use contralateral to the DA-depletion. The contralateral limbs participated less in initiating and sustaining propulsion than the ipsilateral limbs. These deficits secondary to unilateral DA-depletion show that the rotorod provides a use task for the analysis of stepping movements.

The rotorod test is used to assess motor status in the walking movement of hemi-Parkinson analogue rats.

Rotorod Rat Yürüyüş Kalitatif Analiz için bir yöntem olarak kullanımı

High speed videoanalysis of the details of movement can provide a source of information about qualitative aspects of walking movements. When walking on a ...

Biyoloji

The Dig Task: A Simple Scent Discrimination Reveals Deficits Following Frontal Brain Damage

Cognitive impairment is the most frequent cause of disability in humans following brain damage, yet the behavioral tasks used to assess cognition in rodent models of brain injury is lacking. Borrowing from the operant literature our laboratory utilized a basic scent discrimination paradigm1-4 in order to assess deficits in frontally-injured rats. Previously we have briefly described the Dig task and demonstrated that rats with frontal brain damage show severe deficits across multiple tests within the task5. Here we present a more detailed protocol for this task. Rats are placed into a chamber and allowed to discriminate between two scented sands, one of which contains a reinforcer. The trial ends after the rat either correctly discriminates (defined as digging in the correct scented sand), incorrectly discriminates, or 30 sec elapses. Rats that correctly discriminate are allowed to recover and consume the reinforcer. Rats that discriminate incorrectly are immediately removed from the chamber. This can continue through a variety of reversals and novel scents. The primary analysis is the accuracy for each scent pairing (cumulative proportion correct for each scent). The general findings from the Dig task suggest that it is a simple experimental preparation that can assess deficits in rats with bilateral frontal cortical damage compared to rats with unilateral parietal damage. The Dig task can also be easily incorporated into an existing cognitive test battery. The use of more tasks such as this one can lead to more accurate testing of frontal function following injury, which may lead to therapeutic options for treatment. All animal use was conducted in accordance with protocols approved by the Institutional Animal Care and Use Committee.

In this protocol, a novel application of scent discrimination is described. The Dig task is a reasonably inexpensive task that can be used to assess frontally-mediated cognition following brain damage.

Dig Görev: A Simple Scent Ayrımcılık Kesit Beyin Hasarı takiben Açıkları ortaya çıkarır

Cognitive impairment is the most frequent cause of disability in humans following brain damage, yet the behavioral tasks used to assess cognition in ...

Nörobilim

Assessment of Memory Function in Pilocarpine-induced Epileptic Mice

Cognitive impairment is one of the most common comorbidities in temporal lobe epilepsy. To recapitulate epilepsy-associated cognitive decline in an animal model of epilepsy, we generated pilocarpine-treated chronic epileptic mice. We present a protocol for three different behavioral tests using these epileptic mice: novel object location (NL), novel object recognition (NO), and pattern separation (PS) tests to evaluate learning and memory for places, objects, and contexts, respectively. We explain how to set the behavioral apparatus and provide experimental procedures for the NL, NO, and PS tests following an open field test that measures the animals&#8217; basal locomotor activities. We also describe the technical advantages of the NL, NO, and PS tests with respect to other behavioral tests for assessing memory function in epileptic mice. Finally, we discuss possible causes and solutions for epileptic mice failing to make 30 s of good contact with the objects during the familiarization sessions, which is a critical step for successful memory tests. Thus, this protocol provides detailed information about how to assess epilepsy-associated memory impairments using mice. The NL, NO, and PS tests are simple, efficient assays that are appropriate for the evaluation of different kinds of memory in epileptic mice.

This article presents experimental procedures for assessing memory impairments in pilocarpine-induced epileptic mice. This protocol can be used to study the pathophysiologic mechanisms of epilepsy-associated cognitive decline, which is one of the most common comorbidities in epilepsy.

Pilocarpine bağlı Epileptik Farelerde Hafıza Fonksiyonunun Değerlendirilmesi

Cognitive impairment is one of the most common comorbidities in temporal lobe epilepsy. To recapitulate epilepsy-associated cognitive decline in an animal ...

Tracking Rats in Operant Conditioning Chambers Using a Versatile Homemade Video Camera and DeepLabCut

Operant conditioning chambers are used to perform a wide range of behavioral tests in the field of neuroscience. The recorded data is typically based on the triggering of lever and nose-poke sensors present inside the chambers. While this provides a detailed view of when and how animals perform certain responses, it cannot be used to evaluate behaviors that do not trigger any sensors. As such, assessing how animals position themselves and move inside the chamber is rarely possible. To obtain this information, researchers generally have to record and analyze videos. Manufacturers of operant conditioning chambers can typically supply their customers with high-quality camera setups. However, these can be very costly and do not necessarily fit chambers from other manufacturers or other behavioral test setups. The current protocol describes how to build an inexpensive and versatile video camera using hobby electronics components. It further describes how to use the image analysis software package DeepLabCut to track the status of a strong light signal, as well as the position of a rat, in videos gathered from an operant conditioning chamber. The former is a great aid when selecting short segments of interest in videos that cover entire test sessions, and the latter enables analysis of parameters that cannot be obtained from the data logs produced by the operant chambers.

This protocol describes how to build a small and versatile video camera, and how to use videos obtained from it to train a neural network to track the position of an animal inside operant conditioning chambers. This is a valuable complement to standard analyses of data logs obtained from operant conditioning tests.

Çok Yönlü Ev Yapımı Video Kamera ve DeepLabCut kullanarak Operant Klima Odalarında Rats Izleme

Operant conditioning chambers are used to perform a wide range of behavioral tests in the field of neuroscience. The recorded data is typically based on ...

Motor and Hippocampal Dependent Spatial Learning and Reference Memory Assessment in a Transgenic Rat Model of Alzheimer's Disease with Stroke

Alzheimer&#39;s disease (AD) is a debilitating neurodegenerative disease that results in neurodegeneration and memory loss. While age is a major risk factor for AD, stroke has also been implicated as a risk factor and an exacerbating factor. The co-morbidity of stroke and AD results in worsened stroke-related motor control and AD-related cognitive deficits when compared to each condition alone. To model the combined condition of stroke and AD, a novel transgenic rat model of AD, with a mutated form of amyloid precursor protein (a key protein involved in the development of AD) incorporated into its DNA, is given a small unilateral striatal stroke.
For a model with the combination of both stroke and AD, behavioral tests that assess stroke-related motor control, locomotion and AD-related cognitive function must be implemented. The cylinder task involves a cost-efficient, multipurpose apparatus that assesses spontaneous forelimb motor use. In this task, a rat is placed in a cylindrical apparatus, where the rat will spontaneously rear and contact the wall of the cylinder with its forelimbs. These contacts are considered forelimb motor use and quantified during video analysis after testing. Another cost-efficient motor task implemented is the beam-walk task, which assesses forelimb control, hindlimb control and locomotion. This task involves a rat walking across a wooden beam allowing for the assessment of limb motor control through analysis of forelimb slips, hindlimb slips and falls. Assessment of learning and memory is completed with Morris water maze for this behavioral paradigm. The protocol starts with spatial learning, whereby the rat locates a stationary hidden platform. After spatial learning, the platform is removed and both short-term and long-term spatial reference memory is assessed. All three of these tasks are sensitive to behavioral differences and completed within 28 days for this model, making this paradigm time-efficient and cost-efficient.

To investigate the co-morbid Alzheimer&#39;s disease (AD) and stroke condition in a novel model, three behavior tasks are described that assess both motor control and cognitive behaviors. These tasks include the beam-walk task, cylinder task and Morris water maze.

İnme ile Alzheimer Hastalığının bir Transgenik Fare Modelinde Motor ve Hipokampal Bağımlı Mekansal Öğrenme ve Referans Hafıza Değerlendirme

Alzheimer&#39;s disease (AD) is a debilitating neurodegenerative disease that results in neurodegeneration and memory loss. While age is a major risk ...

Tıp

Performing Permanent Distal Middle Cerebral with Common Carotid Artery Occlusion in Aged Rats to Study Cortical Ischemia with Sustained Disability

Stroke typically occurs in elderly people with a range of comorbidities including carotid (or other arterial) atherosclerosis, high blood pressure, obesity and diabetes. Accordingly, when evaluating therapies for stroke in animals, it is important to select a model with excellent face validity. Ischemic stroke accounts for 80% of all strokes, and the majority of these occur in the territory of the middle cerebral artery (MCA), often inducing infarcts that affect the sensorimotor cortex, causing persistent plegia or paresis on the contralateral side of the body. We demonstrate in this video a method for producing ischemic stroke in elderly rats, which causes sustained sensorimotor disability and substantial cortical infarcts. Specifically, we induce permanent distal middle cerebral artery occlusion (MCAO) in elderly female rats by using diathermy forceps to occlude a short segment of this artery. The carotid artery on the ipsilateral side to the lesion was then permanently occluded and the contralateral carotid artery was transiently occluded for 60 min. We measure the infarct size using structural T2-weighted magnetic resonance imaging (MRI) at 24 hr and 8 weeks after stroke. In this study, the mean infarct volume was 4.5% &#177; 2.0% (standard deviation) of the ipsilateral hemisphere at 24 hr (corrected for brain swelling using Gerriet&#8217;s equation, n = 5). This model is feasible and clinically relevant as it permits the induction of sustained sensorimotor deficits, which is important for the elucidation of pathophysiological mechanisms and novel treatments.

Here we present a protocol to produce permanent distal middle cerebral artery occlusion in elderly female rats with simultaneous occlusion of the carotid arteries to generate large cortical infarcts and sustained deficits. We show confirmation of the lesion size using structural MRI at 24 hr and 8 weeks after stroke.

Yaşlı Sıçanlarda Ortak Karotis Arter Tıkanıklığı ile Kalıcı Distal Orta Serebral Sahne Kortikal İskemi Sürekli Engelli Eğitim için

Stroke typically occurs in elderly people with a range of comorbidities including carotid (or other arterial) atherosclerosis, high blood pressure, ...

<meta charset="utf8"></head><body>Miniscope Görüntüleme ile Koku Tüyü Navigasyonu Sırasında Nöronal Aktivitenin Kaydedilmesi

Miniscope Recording Calcium Signals at Hippocampus of Mice Navigating an Odor Plume

Mice navigate an odor plume with a complex spatiotemporal structure in the dark to find the source of odorants. This article describes a protocol to monitor behavior and record Ca2+ transients in dorsal CA1 stratum pyramidale neurons in the hippocampus (dCA1) in mice navigating an odor plume in a 50 cm x 50 cm x 25 cm odor arena. An epifluorescence miniscope focused through a gradient-index (GRIN) lens imaged Ca2+ transients in dCA1 neurons expressing the calcium sensor GCaMP6f in Thy1-GCaMP6f mice. The paper describes the behavioral protocol to train the mice to perform this odor plume navigation task in an automated odor arena. The methods include a step-by-step procedure for the surgery for GRIN lens implantation and baseplate placement for imaging GCaMP6f in CA1. The article provides information on real-time tracking of the mouse position to automate the start of the trials and delivery of a water reward. In addition, the protocol includes information on using an interface board to synchronize metadata describing the automation of the odor navigation task and frame times for the miniscope and a digital camera tracking mouse position. Moreover, the methods delineate the pipeline used to process GCaMP6f fluorescence movies by motion correction using the NorMCorre algorithm followed by identification of regions of interest with EXTRACT. Finally, the paper describes an artificial neural network approach to decode spatial paths from CA1 neural ensemble activity to predict mouse navigation of the odor plume.

<meta charset="utf8"></head><body>Yazar Spotlight: Gerçek Zamanlı Davranış Analizi ile Koku Alma ve Mekansal Bilgilerin Beyin Tarafından İşlenmesini Anlama

This protocol investigates the brain-behavior relationship in hippocampal CA1 in mice navigating an odor plume. We provide a step-by-step protocol, including surgery to access imaging of the hippocampus, behavioral training, miniscope GCaMP6f recording and processing of the brain, and behavioral data to decode the mouse position from ROI neural activity.

Bir koku bulutunda gezinen farelerin hipokampusunda kalsiyum sinyallerini kaydeden miniskop

Mice navigate an odor plume with a complex spatiotemporal structure in the dark to find the source of odorants. This article describes a protocol to ...

Rat fimbria-forniks Lezyonlar Koku Takibi sonra ancak Engelli Dead Reckoning Pilotaj Korunan bir video gösteri

Özet

Daha Fazla Video Keşfet

Bu videodaki bölümler

Çift H Maze: Kemirgenler A Sağlam Davranış Öğrenme için test ve Hafıza

Travmatik beyin hasarı sonra Sıçanlarda algılama davranış açıkları

Rotorod Rat Yürüyüş Kalitatif Analiz için bir yöntem olarak kullanımı

Dig Görev: A Simple Scent Ayrımcılık Kesit Beyin Hasarı takiben Açıkları ortaya çıkarır

Pilocarpine bağlı Epileptik Farelerde Hafıza Fonksiyonunun Değerlendirilmesi

Çok Yönlü Ev Yapımı Video Kamera ve DeepLabCut kullanarak Operant Klima Odalarında Rats Izleme

İnme ile Alzheimer Hastalığının bir Transgenik Fare Modelinde Motor ve Hipokampal Bağımlı Mekansal Öğrenme ve Referans Hafıza Değerlendirme

Yaşlı Sıçanlarda Ortak Karotis Arter Tıkanıklığı ile Kalıcı Distal Orta Serebral Sahne Kortikal İskemi Sürekli Engelli Eğitim için

Bir koku bulutunda gezinen farelerin hipokampusunda kalsiyum sinyallerini kaydeden miniskop

Bir koku bulutunda gezinen farelerin hipokampusunda kalsiyum sinyallerini kaydeden miniskop